Studies On The Electrochemical Properties Of The Doped In LiV₃O₈Cathod Material Of Lithium-ion Battery

In the21st century, the relationship between electrochemical and energy is paid more and more attention. Lithium-ion battery which is to be a new type of green energy is accessing to all areas of human society quickly, and get great use. To a great extent, Lithium-ion battery has been able to influence People’s Daily life. Lithium-ion battery has high energy density, high output voltage, long cycle life, safely fast charge and discharge. Compared with lithium-metal battery, lithium-ion battery has a short circuit resistance, impact resistance, shock-proof, resistance to overcharge and discharge, etc. And lithium-ion battery does not contain harmful metals such as cadmium, lead, mercury, and won’t cause pollution to the environment, is the most potential of the third generation green battery. Lithium-ion battery has no memory, it can be repeated charge and discharge. At the same time, Lithium ion battery has excellent low-temperature discharge performance. In view of these excellent properties of lithium-ion battery, Research on lithium-ion has become the focus of new green energy, and the performance of cathode materials for lithium-ion determines the performance of lithium ion battery directly.The first chapter of this paper introduces the principle of lithium-ion battery, the history of lithium-ion battery, requirement for lithium-ion battery the anode material, and research progress of cathode materials. The second chapter to the fourth chapter mainly introduces the different production process of vanadium acid lithium composite cathode material, and according to the methods of SEM, XRD, analysis of the composition of the phase diagram of composite materials, testing electrochemical performance, analysis of discharge capacity, first cycle performance, coulombic efficiency etc.(1) It researches the electrochemical properties of the Compound (Nao.iLio.9V3O8) which is synthesized by sol-gel method of doped Na vanadium acid lithium. The research shows that doping Na can effectively change the cycle performance and discharge capacity of vanadium acid lithium. The first discharge capacity of lithium-ion battery is up to253.5mA·h/g, and capacity after20cycles can maintain the220mA·h/g still.(2) It tests the electrochemical properties of the Compound (K0.1Li0.9V3O8) which is synthesized by sol-gel method of vanadium doped with K acid. The results show that lithium-ion battery with K can improve large current discharge performance of material, boost to charge and discharge capacity. In the range of1.5V to4.0V, the first discharge capacity of battery is up to295.3mA·h/g, the coulomb efficiency is up to99.9%. When high current density (0.6mA/cm2) discharge in the range of2.0V-4.0V, the discharge capacity of lithium-ion battery is up to272.5mA·h/g.(3) It tests the electrochemical properties of cathode material (LiV3O8) with lithium-ion battery, which is used the method of low temperature solid phase. And it discusses how much influence on electrochemical properties of zinc element content is. The results show the battery first discharge capacity is up to is257.82mA·h/g, and the coulomb efficiency is up to99.9%. After20cycles of charge and discharge capacity is up to234mA·h/g, the coulomb efficiency is up to99.78%. Therefore, Capacity fade slowly, the coulomb efficiency is greatly improved.